XVI. V o s t i c e u a .
Vermis contraQilis, nudus, ciliis rotatoriis. A worm capable
o f contracting or extending itfelf, naked, with rotatory cilia.
283. Vorticella Viridis. Fig. 31, Plate XX VL
Vorticella cylindracea, uniformis, viridis opaca. Cylindrical,
uniform, green, and opake.
T o the naked eye it appears as a fmall green point, through
the microfcope as an opake corpufcle, o f a dark-green colour,
cylindrical, obtufe at both extremities, yet rather thicker in the
fore-part a ; very fimple, deftitute o f limbs, not changing it’s
figure. Notwithftanding it’s fimplicity, the continual motion
into which it puts the water gives room to fufpeft that it is fur-
nifhed with an invifible rotatory inflrument, it moves fometimes
circularly, fometimes in a flrait line, a the fore-part, b the hind-
part, c fhort hairs.
284. VorticeHa Sphasroida.
Vorticella cylindrico-globofa, uniformis, opaca. A globous
•cylinder, uniform and opake.
T o the naked eye it appears little more than a point fwimming
about in the water; but with the microfcope as a globular mafs,
o f a dark-green colour ; they occafion a vehement motion in the
adjacent
adjacent water, very, fhort hairs, which are probably the caufe
thereof, may be perceived,
285. Vorticella Cincla. Fig. 30, Plate XXVI.
Vorticella trapeziformis, nigro-viridis, opaca. This vorticella
is in the form of a trapezium, of a blackifh green colour, and
opake.
It is o f an irregular figure, invifible to the naked eye, ciliated
on every fide, the hairs all moveable, and longer on one fide
than on the other. It fometimes affumes an oval fhape, and appears
girt round with a tranfverfal keel.
286. Vorticella Lunifera.
Vorticella viridis, poftice lunata, medio margine mucronato.
Green vorticella, the hinder-part lunated, with a point in the
middle, projefling from the edge.
The fore-part obtufe, the bafe broad, and hollowed away like
a crefcent, with a protuberance in the middle o f the concave
part, fhorter than the horns or points o f the crefcent; the forepart
is ciliated. ~ It is found in fait water.